CN106659860B

CN106659860B - Ventilation mask

Info

Publication number: CN106659860B
Application number: CN201580044737.6A
Authority: CN
Inventors: 迈克尔·J·佩德罗; 史蒂文·H·卡塔尔多; 托马斯·M·雷利; 赖安·G·雷德福德; 大卫·M·凯恩
Original assignee: Revolutionary Medical Devices Inc
Current assignee: Shunmei Group Holdings Ltd
Priority date: 2014-08-20
Filing date: 2015-08-07
Publication date: 2020-07-28
Anticipated expiration: 2035-08-07
Also published as: US20220257893A1; AU2015305893A1; CN111921054A; AU2021261980C1; MX2017000753A; US20170173291A1; AU2020204637B2; AU2021261980B2; CR20170016A; US20190232012A1; AU2015305893B2; US11324909B2; EP3183023B1; CA2958557A1; SG11201701253UA; JP6496402B2; EP3183023A4; AU2021261980A1; EP3848077B1; BR112017003289A2

Abstract

The application discloses a nasal ventilation mask with a device for monitoring end-tidal CO₂A separate port for exhalation integrated into the mask to monitor end-tidal CO exhaled by the nose or mouth₂. The present application also discloses a CPR mask for nose-to-mouth and/or mouth-to-mouth resuscitation having a body shaped to cover the nose and/or mouth of a victim, the mask comprising CO₂An absorbent for at least partially eliminating CO exhaled by the rescuer that is transmitted to the victim₂。

Description

Ventilation mask

This application claims priority to U.S. provisional application 62/039,759 filed on 8/20 of 2014, U.S. provisional application 62/078,677 filed on 11/12 of 2014, and U.S. provisional application 62/161,041 filed on 5/13 of 2015, which are incorporated herein by reference in their entirety.

Technical Field

The present invention relates to improvements in anaesthetic and ventilation masks.

Background

During surgery, the patient is typically under anesthesia. The most commonly used delivery systems consist of a canister containing anesthetic gases and oxygen, a system for regulating the flow of gases and the breathing of the patient, and equipment for ensuring that the patient's airways are capable of breathing, oxygenating, and delivering a mixture of anesthetic gases. During emergency and/or selective airway control, a ventilation mask is used to provide oxygen to the patient; the selective airway control process includes, but is not limited to: before a patient is anesthetized for surgery, while the patient is anesthetized, while the patient is sedated during surgery or treatment, while the patient is recovering from anesthesia, after the patient is recovering from anesthesia, or in any case where the patient requires oxygen delivery. However, one of the drawbacks of mask ventilation is that it requires constant contact between the provider's hands and the patient's face to hold the mask in place and the patient in the sniffing position to ensure that oxygen and anesthetic gases do not leak into the air and that the patient's airway remains open. Known dangerous complications of upper airway obstruction may occur if the provider does not maintain the patient in the sniffing position. The reasons that providers need to perform continuous ground cover retention and manipulation are due to human anatomy and physiology. When the muscles of the jaw, tongue and upper airway relax due to sedation and/or muscle relaxants and/or anesthesia given to the patient for sedation, the upper airway (mouth, pharynx, larynx) may become partially occluded and may close completely. When the patient's jaw is lowered and the tongue obstructs the airway, it can cause snoring (partial obstruction) or asphyxia (complete inability to get oxygen through the upper airway into the lungs). Another problem exists when the provider fails to administer sufficient anesthesia or sedation, or it begins to taper and the patient begins to move. This may also cause obstruction of the patient's airway as the patient's head and neck position is no longer in the sniffing position. Patient movement during surgery is also dangerous as it can lead to surgeon error, particularly in eye, ear, nose, neck, head and throat surgery.

In addition, situations may arise during surgery where rapid intubation of the patient is required. Full face masks, i.e. masks that cover the nose and mouth of a patient, are problematic in emergency situations because the mask must be removed to expose the patient's mouth for intubation. However, removing the mask also removes the oxygen support. The present invention, as will be described below, solves the above-mentioned and other drawbacks of the prior art in one aspect.

Another aspect of the invention relates to a cardiopulmonary resuscitation (CPR) mask.

Cardiopulmonary resuscitation, commonly referred to as CPR, is a first aid procedure implemented to manually preserve intact brain function until further measures can be taken to restore spontaneous blood circulation and respiration in a patient (hereinafter "subject" or "victim") who is in a cardiac arrest state. CPR is also applicable in non-responsive patients who are not breathing, for example in the case of drowning victims, or victims of shocks or abnormal breathing, for example, non-breathing.

CPR involves chest compressions at a depth of at least two inches and is performed at a rate of at least 100 beats per minute to create artificial circulation by manually pumping blood through the heart and thus through the body. The rescuer may also provide breathing by exhaling directly into the mouth of the subject, or through a CRP mask to the mouth and/or nose of the subject (collectively "mouth-to-mouth" resuscitation), or using a device that pushes air into the lungs of the subject through the mouth and/or nose of the subject. The method of externally providing ventilation is known as "artificial resuscitation". Current proposals emphasize high quality chest compressions for manual resuscitation; however, when combined with high quality chest compressions, artificial resuscitation potentially provides the greatest benefit to the patient.

Conventional CPR masks are held in place by the CPR provider by hand or may be held in place by straps that extend behind the head of the subject or victim. While CPR masks may assist in the ventilation of non-breathing individuals or victims, when rescuers provide mouth-to-mouth and/or nose-to-mouth resuscitation, the supplied air contains significant amounts of lethal CO₂. As will be discussed below, the present invention, in another aspect, addresses the above-noted and other shortcomings of the prior art.

Disclosure of Invention

The present invention, in one aspect, provides an improved ventilation/anesthesia mask that overcomes the above-referenced and other problems of the prior art. More particularly, a nasal ventilation/anesthesia mask is provided that includes one or more offset gas openings to allow a provider to have a clear view of the mouth and airway during direct laryngoscopy and intubation, consisting of: a ventilation port for supplying oxygen and other gases during anaesthesia by non-invasive positive pressure ventilation (NIPPV) and which is connected to a device capable of measuring nasal end-tidal CO₂The anesthesia circuit of (a); an oral opening port under the nose for purging anesthetic gases and end-tidal CO exhaled by the patient's mouth₂(ii) a Gas purification/end-tidal CO₂A port connected to a passage in the mask interior, which is isolated from the nasal cavity; and an oxygen port for supplying postoperative oxygen. The mask is provided with a plurality of tabs or eyelets, preferably three or four, for attaching the mask to the head of a patient or for attaching the mask down to the operating table, for example as taught in our co-pending PCT application PCT/US14/44934 and co-pending PCT application PCT/US 15/34277.

In one embodiment of the present invention, a nasal ventilation mask is provided having O for introducing oxygen into the mask₂A port, a ventilation port, and a gas monitoring accessory integrated into or connected to the ventilation port. In such an embodiment, the gas monitoring port includes a luer lock.

In another embodiment of the invention, there is provided a nasal ventilation mask having an external opening below the nasal region of the mask and above the patient's lip region that allows exhaled gas from the mouth to be purified and delivered to a purification device, the mask preferably further comprising a purification line for diverting a portion of the exhaled gas to monitor end-tidal CO₂And wherein the connector is preferably arranged at the end-tidal CO₂The monitoring line effectively diverts the gas flow at a location where it intercepts the purge line, resulting in a CO relative to the end-tidal₂Positive pressure of the line, thereby allowing gas to be sampled by the purge line.

In such an embodiment, the mask may further include a 2-channel, 3-port valve controlled by the anesthesiologist, allowing the anesthesiologist to monitor end-tidal CO separately₂Switching between nasal and oral exhalations or simultaneously monitoring when a valve opens both, wherein CO ends when the mouth exhales₂End-tidal CO when a monitoring port is selected₂The monitoring line is preferably also used for purging other ventilation gases during anaesthesia.

The present invention also provides a nasal ventilation mask having tabs or eyelets for attaching the mask anteriorly to a mask holder or posteriorly to a conventional anaesthetic mask strap, the mask optionally further characterised by one or both of the following features:

(a) allowing only one engaged front-rear headband to be connected, wherein the rear headband may be connected to the mask alone, or may be connected to the mask and then connected to a surface that will prevent movement of the patient's head and/or neck; or

(b) The patient's head is secured to the support surface using headgear, wherein the patient's head will remain in the target position and the support surface will remain in the target position when the provider changes the head and/or neck angle.

In yet another embodiment of the present invention, a nasal mask is provided that is characterized by one or more of the following features:

(a) wherein the mask can be used as an oxygen delivery mask or a ventilation mask, providing O₂And anesthetic gases for simultaneous monitoring of end-tidal CO₂；

(b) Having means for monitoring end-tidal CO through one or more ports₂The port of (a), which can be used for CPAP before, during and after surgery;

(c) having means for monitoring end-tidal CO through one or more ports₂May be connected to the resuscitation bag in such a way that the patient's mouth and airway are not obstructed by the resuscitation bag, thereby allowing direct laryngoscopy and intubation;

(d) wherein the mask can be attached anteriorly to a mask holder or posteriorly using a conventional anaesthetic mask strap; and

(e) with O for introducing oxygen into the mask₂A port, a ventilation port and a gas monitoring accessory integrated or connected to the ventilation port, wherein the gas monitoring port preferably comprises a luer lock.

The invention also provides an anaesthetic mask having a built-in purging system for collecting anaesthetic gases that leak out near the mouth and/or nose.

In yet another embodiment, the invention provides a chin strap for a submental space connected to a nasal mask for applying pressure to force a wearer's tongue against the soft palate and cause obstruction of the retrolingual space, thereby reducing or preventing leakage of gas out of the patient's mouth and allowing the patient to exhale from the nose, wherein the chin strap is further capable of releasing pressure during exhalation to prevent obstruction of the exhalation if desired.

In another aspect, the present invention provides an improved CPR mask for mouth-to-mouth and/or nose-to-mouth resuscitation and comprising CO₂Absorbents that eliminate CO exhaled by rescuers or providers rebreathing victims₂. More particularly, the present invention provides a CPR mask comprising CO built into the mask or mask access interior₂Filters or absorbents for absorbing CO exhaled by rescuers or providers₂。

That is, a CPR mask for mouth-to-mouth and/or nose-to-mouth resuscitation comprising a body shaped to cover the nose and/or mouth of a victim, the mask comprising CO₂An absorbent for eliminating at least a portion of CO exhaled by the rescuer that is transmitted to the victim₂。

In one embodiment, CO₂The absorbent is coated on the inner surface of the mask.

In another embodiment, the mask comprises a ventilation tube, wherein the CO is₂The absorbent is located in the ventilation tube.

In another embodiment, the mask includes a one-way valve and/or a strap for holding the mask to the head of the victim.

In one embodiment, the mask includes a flexible periphery that conforms to the face of the victim. In such embodiments, the periphery may include a soft, compliant air bladder, or a resiliently deformable foam pad.

In another embodiment, the mask includes a biological filter that is incorporated into the mask interior or is coupled to the ventilation tube.

In yet another embodiment of the present invention, a CPR mask as described above is provided, further characterized by one or more of the following features:

(a) comprises a one-way valve;

(b) comprising a strap for holding the mask to the head of the victim;

(c) wherein the mask further comprises a flexible periphery for conforming to the face of the wearer, wherein the periphery preferably comprises a soft, pliable air bladder or an elastically deformable foam pad.

Drawings

Other features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which

FIGS. 1a and 1b are front and top views of a nasal ventilation mask according to a first embodiment of the present invention;

FIG. 2 is an interior view of the ventilation mask of FIG. 1 a;

FIGS. 3a and 3b are plan views showing a ventilation mask according to the present invention positioned on a patient's head;

FIGS. 4a and 4b are views similar to FIGS. 3a and 3b showing the chin strap attached to the mask;

FIGS. 5a and 5b show a device with end-tidal CO according to the invention₂Alternative structures for the nasal mask of the monitor;

FIG. 6 is a side view of an alternative configuration of a nasal mask ventilation system according to the present invention;

FIG. 7 is a schematic representation of a reactor with CO according to the present invention₂A plan view of an alternative embodiment of a nasal ventilation mask of the monitor;

FIG. 8 is a schematic representation of a reactor with CO according to the present invention₂A plan view of another alternative configuration of the nasal mask of the monitor;

figure 9 is a partial cross-sectional view of a CPR mask according to a first embodiment of the invention;

figure 10 is a side view of a second embodiment of a CPR mask according to the invention.

Detailed Description

A nasal ventilation mask 10 according to a first embodiment of the invention is shown in figures 1a and 1 b. Most preferably, it contains four gas openings, but may also contain less or more than four. The first is a ventilation port 12 which supplies O during anaesthesia or for NIPPV in critically ill patients₂And other gases, and allows the patient to be saved from any end-tidal CO exhaled by the nose₂. The second is an oral opening 14 which is located below the nose but is isolated from the nasal cavity formed by the mask which is located above the patient's nose. The purpose of the opening 14 is to purge the anesthetic gases and end-tidal CO exhaled from the patient's mouth₂. In addition to reducing or avoiding anesthetic gases from entering the surgical suite and becoming a hazard, it allows end-tidal CO to be expelled from the patient's lungs and escape through the mouth₂Is monitored. Third opening for gas purification/end-tidal CO₂A port 16 connected to the opening by a passage 18 inside the mask that is isolated from the nasal cavity (see fig. 2). End-tidal CO including arbitrary exhalations₂Exits the mask through port 16 and is directed to a gas purification filter and end-tidal CO through tube 20₂A monitor 32 (see fig. 3), the monitor 32 sampling gas originating from the gas purge line. The fourth opening is O₂Port 22, which is unsealed during anesthesia and may be connected to O, whether before, during, or after surgery₂A source (not shown). When O is present₂When supplied, the ventilation tube is disengaged from the ventilation port 12, thereby allowing end-tidal CO₂Can be exhaled through the nose. A gas shield 24 located under the nose, around the mouth opening 14, extends beyond the mask as shown. Which is optionally included to expand the influence of the mouth opening 14 in the mask, therebyContaining a greater percentage of the gas exhaled by the patient.

The mask also includes three eyelets or tabs 60, 62, 64, or four eyelets or tabs 66, 68, 70, 72 (fig. 7) for attaching chin straps or head straps as described below, or for attaching straps to the operating table, as taught in our co-pending application PCT/US14/44934 or our co-pending PCT application PCT/US 15/34277.

An interior view of the nasal ventilation mask 10 of the present invention is depicted in fig. 2. Vent ports 12 and O₂The port 22 is connected to a nasal cavity 26. The gas exhaled by the mouth travels from the mouth opening 14 outside the mask through the gas passage 18 and from the purification device and the end-tidal CO₂Gas purifier and end-tidal CO on monitor₂The monitoring port 16 is exhausted. The gas passages 18 separate the nasal cavities 26 formed by the ventilation mask over the nasal and oral areas of the patient.

When O is present₂Or O₂And anesthetic gases are supplied to the patient, they travel through the ventilation pathway 28 connected to the ventilation port 12 to the nasal cavity, the oxygen port being sealed at 30 by a cap shown in phantom. After surgery, the cap 30 may be made of O₂Port 22 is removed and O₂A pipeline is connected to the port to connect O₂Is administered to a patient. Ventilation pathway 28 is removed by ventilation port 12 and nasal cavity 26 is open to atmosphere with end-tidal CO₂Can be exhaled through the nose.

For nasal mask ventilation/end-tidal CO₂Monitor oral gas purifier/end-tidal CO₂The gas circuit of the monitoring line is shown in fig. 3a and 3 b. Fig. 3a shows nasal airflow originating from the nasal cavity 26, said nasal cavity 26 being connected to a ventilation pathway 28 and end-tidal CO₂The device 32 is monitored. FIG. 3b shows that gas exhaled by the mouth enters the mouth opening and flows through the gas purge line to the recovery apparatus 34 and associated lines connected to the purge line and to the end-tidal CO₂And (5) monitoring equipment. Note that: the opening to the purge line should be placed at about 90 deg. to the purge gas flow so that the local pressure is higher than if the opening were perpendicular to the gas flow. If it is vertical, then due to the negativityPressure gradient, negative pressure will prevent end-tidal CO₂A monitor line samples the gas stream.

Referring also to fig. 4a and 4b, chin strap 36 may also be applied to the submental space, connected to nasal mask 10, and apply pressure to force the tongue against the soft palate and cause obstruction of the retrolingual space, which will help prevent any air from leaking out of the patient's mouth and allow the patient to exhale through the nose. The chin strap 36 also has the ability to release pressure during exhalation, if desired, to prevent obstruction of exhalation and to allow end-tidal CO₂And other gases are released from the mouth.

In an alternative configuration, for nasal mask ventilation and end-tidal CO₂The monitored gas circuit is depicted in fig. 5a and 5 b. The figure shows a two-way three-port valve 40 connecting the nasal circuit to the end-tidal CO₂And (5) monitoring equipment. The anesthesiologist decides which region (nasal region, oral region, or both) should be monitored for end-tidal CO₂。

Nasal mask ventilation and monitoring of end-tidal CO from the oral airways₂A side view of an alternative structure for exhalation is shown in fig. 6. Note that the two-way three-port valve 40 has been flipped in the direction of the mouth for end-tidal CO₂Sampling is performed.

Nasal ventilation masks also allow only one combined front-back headband to be attached, which can be connected to the mask alone, or can be connected to the mask and then connected to a surface, which will prevent movement of the patient's head and/or neck. When the provider changes the head and/or neck angle, the patient's head will remain in the target position and the support surface will remain in the target position by securing the patient's head to the support surface using the headgear.

FIG. 7 depicts yet another embodiment of the present invention wherein O is passed₂The line provides oxygen to the patient, said O₂O connected to ventilation mask₂A port. The exhaled gas is vented to atmosphere through the ventilation port 12, as shown in fig. 7. If the patient is unconscious due to anesthesia, it is necessary to ensure that the CO is present₂Will be called out. This can be achieved by addingThis is accomplished by adding a "T-shaped" gas monitoring attachment 50 that slides onto the mask ventilation port 12. The body of the tubular fitting 50 allows exhaled gas to be vented to atmosphere. The side of the attachment is a tubular opening 52, nominally 90 ° from the side. The end of the opening 52 may have a luer lock or any other kind of fastening connection. If a gas monitor line 54 connected to a gas monitor is connected to the gas monitor line interface, exhaled gas from the main gas flow may be sampled through the opening.

An alternative method for achieving the same gas sampling features is depicted in fig. 8. In this embodiment, the gas monitoring line interface is an integral component of the mask ventilation port 12. In this structure, O₂Flows to O through the supply line₂Within the port and exhaled gases pass to atmosphere through the ventilation port 12. The side of the ventilation port 12 is a tubular opening 56, nominally 90 ° from the side. The open end may have a luer lock, or any other kind of secure connection. If a gas monitoring line connected to a gas monitor is connected to the gas monitoring line interface, exhaled gas from the main gas flow may be sampled through the opening.

Referring to fig. 9, a first embodiment of a CPR mask, indicated generally at 110, according to another aspect of the invention is shown for use in effecting rescue breaths, mouth-to-mouth resuscitation, or any other CPR step requiring emergency respiratory assistance. The mask 110 is shaped to cover the nose and/or mouth of the victim and includes a soft and pliable periphery 112 for conforming to the face of the victim when moderate force is applied to achieve a tight fitting mask seal. Typically, the periphery 112 of the mask includes a soft, pliable air bladder 114 or a resiliently deformable foam pad or the like.

Ventilation tube 116 is connected to an integral inlet port 118 projecting from the mask through which air can be supplied to the tube by the rescuer via exhalation. Ventilation tube 116 or inlet port 118 typically includes a one-way valve 120 that allows air to enter the mask through tube 116. Ventilation tube 116 and its associated valve 120 may be integrally formed with port 118 or may be a replaceable, disposable element or assembly (fig. 10).

The inner surface 122 of the mask 110 is made of CO₂The adsorbent material (e.g. activated carbon or zeolite) is partially coated. Also, certain minerals such as serpentine may be advantageously employed. Typically, these materials are selected to be optimally sized and encapsulated in a filter material 124 that is bonded to the inner surface 122 of the mask 110. Alternatively, the inner surface 122 of the mask 110 may be coated with CO₂Absorbent polymers, such as polyethyleneimine containing fumed silica, are described on page 33 of Scientific American, 1/6/2012.

Alternatively, as shown in FIG. 10, containing CO₂Absorbing CO of a material₂A filter 126 may be incorporated into ventilation tube 116.

In use, a rescuer places a CPR mask 110 over the nose and/or mouth of the victim to begin emergency ventilation of the victim. The rescuer applies moderate force to obtain a substantially airtight seal against the victim's face, and then provides ventilation by the rescuer exhaling into the ventilation tube 116. Although the rescuer exhales and contains CO₂But the vast majority of CO₂Will pass through CO₂The filter material is removed.

The mask 110 may be formed in different sizes, such as adult size, young age size, and child size, to accommodate different sized faces. A feature and advantage of the CPR mask of the present invention is that the CO supply to the victim is significantly reduced₂Amount of the compound (A). Moreover, the mask helps protect victims and rescuers in an emergency situation by preventing the spread of disease.

Various changes may be made to the invention described above without departing from the spirit and scope of the invention. For example, a biological filter (130 shown in phantom in fig. 10) may also be incorporated into the mask or ventilation tube 116. Additionally, the mask may include straps 132 for attaching the mask to the head of the victim, thereby saving the rescuer from having to press the mask against the face of the victim. Other variations are also possible.

Claims

1. A nasal ventilation mask having a body defining a nasal cavity with an interior, the body being configured to cover a patient's nose while leaving a patient's mouth uncovered, the mask having an O₂Port, ventilation port and end-tidal CO₂Port of said O₂A port is fluidly connected to the nasal cavity for introducing oxygen into the nasal cavity, and a ventilation port is fluidly connected to the nasal cavity for directing gas toward or away from the nasal cavity, the end-tidal CO₂A port fluidly connected to an external opening below a nose region of the mask, adapted to cover a lip region of a patient, wherein the end-tidal CO₂A port is configured to be coupled to the monitoring line, a ventilation port is configured to be coupled to a ventilation line, and the external opening is adapted to exclude exhaled gas from the wearer's mouth.

2. The mask of claim 1, further comprising integrated end-tidal CO₂A monitor for monitoring end-tidal CO exhaled by the nose and mouth of the patient₂Wherein the mask is adapted to function as an oxygen delivery mask or as a supply of O₂And a ventilation mask for anesthetic gases.

3. The mask of claim 1, wherein the mask is adapted for pre-operative, intra-operative and/or post-operative cpap.

4. The mask of claim 1, wherein the mask is adapted to be connected to a resuscitation bag such that the patient's mouth and airway are not obstructed by the resuscitation bag, thereby allowing direct laryngoscopy and intubation.

5. The mask of any one of claims 1-4 having a gas monitoring attachment integrated or attached to a ventilation port.

6. The mask of any one of claims 1-4, further comprising a bi-directional three-port valve controlled by an anesthesiologist to allow the anesthesiologist to monitor the end of nasal and oral exhalations, respectivelyCO₂Or simultaneously monitoring nasal and oral end-tidal CO₂Switching between when chosing oral end-tidal CO₂During monitoring, the ventilation gas exhaled by the mouth of the patient is also monitored.

7. The mask of any one of claims 1-4, further comprising a purge line for diverting at least a portion of purge gas to end-tidal CO₂A monitor.

8. The mask of claim 7, wherein the CO is present at the end of expiration₂Providing a connector at the location where the monitoring line intercepts the purge line, diverting the gas flow, resulting in CO relative to the end-tidal₂Positive pressure of the line, thereby allowing gas to be sampled by the purge line.

9. The mask of any one of claims 1-4, further comprising a built-in purging system for collecting anesthetic gases that may leak around the mouth and nose of a patient.

10. The mask of any of claims 1-4, further comprising a tab or eyelet for attaching the mask anteriorly to a mask retainer or posteriorly to a conventional anesthesia mask strap, the mask further characterized by one or both of the following features:

(a) adapted to receive a combined front-rear headband connected to the mask alone or to the mask and a support surface to hold the patient's head and/or neck against movement; and

(b) it is suitable to fasten the head of the patient to the support surface using a headband, wherein the head of the patient and the support surface remain in the target position even if the provider changes the angle of the head and/or neck of the patient.

11. The mask of claim 1, wherein the mask is attached at the front to a mask retainer or at the back to a conventional anaesthetic mask strap.

12. A mask as claimed in any one of claims 1 to 4, the mask having a chin strap for the patient's submental space connected to the nasal mask for applying pressure to force the patient's tongue against the patient's soft palate and to cause obstruction of the retrolingual space, thereby reducing or preventing escape of gas from the patient's mouth and allowing the patient to exhale from the nose, wherein the chin strap is used to release pressure during exhalation to prevent obstruction of exhalation, if required.

13. The mask of claim 1, wherein the mask comprises one gas passage within a chamber, wherein the gas passage will end-tidal CO₂A port is fluidly connected to the external opening and is configured to isolate exhaled gas from the other portions of the chamber.